Field of the Invention
There is an ever-increasing demand for native hardwoods, but commercial farming of this class of trees is frustrated by the slow growth of this class of trees and the difficulty in transplanting them. Similarly, non-commercial reforestation with hardwoods is frustrated by the slow growth and transplantation difficulties. “Traditional” production methods for native hardwoods such as Oaks, Hickories, Ash, Nut trees and others are notoriously slow growing and tend to develop a coarse, carrot-like dominant tap root which makes them very difficult to transplant both in the nursery and especially in out-planting situations—where mortality rates often ran as high as 70 percent or more.
To try and overcome the problems associated with transplantability of native hardwoods and other difficult to transplant species, many nurseries began to “root-prune” their plants while in the field one to three years prior to sale in hopes of developing a “secondary” root system which would give this class of plants a better chance of surviving the out-planting process. The major problem associated with root-pruning in the field is that it not only “shocks” the plants because its root system has been severed but also halts growth and forces the grower to “wait” for another year or more for the root system to re-develop. Although the process of root pruning in the field greatly helped to minimize loss after out-planting, the process was slow, costly and extended the time a plant must remain in the nursery.
One prior art method of root pruning is disclosed in Huang and Liang, Effects of Air-Pruning on Cutting and Seeding Growth in Container Tree Propagation, SNA Research Conference 1987, incorporated herein by reference, pages 134-137.